1. Field of the Invention
This invention relates generally to VoIP communication carriers. More particularly, it relates to location-based services for the provision of E-9-1-1 emergency services by the VoIP industry.
2. Background of Related Art
911 is a phone number widely recognized as an emergency phone number that is used by emergency dispatch personnel, among other things, to determine a location of a caller. Enhanced 911 (E911) is defined by the transmission of callback number and location information. E911 may be implemented for landline and/or wireless devices.
Some Public Safety Access Points (PSAPs) are not enhanced, and thus do not receive the callback or location information from any phone, landline or wireless.
Voice-Over-Internet Protocol (VoIP) is a technology that emulates a phone call, but instead of using a circuit based system such as the telephone network, utilizes packetized data transmission techniques most notably implemented in the Internet.
As people adopt voice-over-IP (VoIP) technology for routine communications, the inventor herein recognizes that there is a growing need to be able to access E911 services including provision of location information from a VoIP device. The existing E911 infrastructure is built upon copper wire line voice technology and is not compatible with VoIP.
There are at least three VoIP scenarios that require E911 service:                1. The VoIP device is physically connected to a static data cable at a “home” address.        2. The VoIP device is physically connected to a data cable at a location different than its “home” address. For instance, a laptop computer device utilized away from home as a VoIP communication device would be a VoIP ‘visitor’ device as described by this scenario.        3. The VoIP device is wireless, physically disconnected from any data cable. In this situation, the VoIP device connects to the VoIP network via cellular or WiFi technology.        
Conventional VoIP voice gateways are typically located in only a few places across the country. Thus, any 911 call originating in a city such as Miami, for example, may initially be routed to the public safety answer point (PSAP) in, e.g., Minneapolis if the VoIP gateway happens to be located in Minneapolis. Moreover, the call will not be “enhanced”. That is, it will not provide any location or callback information to the dispatcher. This problem has been partially resolved as described in FIG. 2.
As shown in FIG. 2, a conventional architecture routes VoIP 911 calls to a designated PSAP. However, such architecture fails to provide “enhanced” service for VoIP devices.
In particular, as shown in Option 1, an IP device 250 utilizing VoIP protocols for voice communications dials 9-1-1. The VoIP device 250 is serviced by a VoIP switch 220 in the VoIP carrier's network. The VoIP switch 220 communicates with a Message Servicing Center (MSC) 230. Using a database that relates the devices callback number or IP address to the owner's address, the MSC 230 can determine which PSAP has jurisdiction for that address. The MSC 230 then communicates back to the VoIP switch 220 a 10-digit telephone number for that PSAP. The VoIP Switch 220 then converts the IP call to TDM and routes the call via the PSTN to the designated PSAP using the provided 10-digit number.
A primary challenge results from the fact that the E911 network is not accessible via the Public Switched Telephone Network (PSTN); all enhanced 911 calls must be routed via dedicated local voice trunks to a selective router that in turn routes the call to the PSAP. Calls routed via the PSTN arrive at the PSAP without callback number or location information. Provision of location information to the PSAP via the PSTN also circumvents specific PSAP hardware (e.g., CAD, GIS) designed to facilitate dispatching of responders and tracking the location of the wireless caller.
There is a need for an architecture and methodology to allow VoIP users all features relating to E911 services enjoyed by non-VoIP users, e.g., call back phone number and location information provided to a public safety answer point (PSAP).